1. Technical Field
The present application relates generally to an improved data processing system and method. More specifically, the present application is directed to a feature for automatically adjusting scheduled inventory of fabrics following fabric merges and segmentations.
2. Description of Related Art
Fibre channel (FC) storage area networks (SANs), or fabrics, are comprised of one or more fibre channel switches. The fibre channel switches are connected to each other through inter-switch links (ISLs), which are active fibre channel cable connections from a port on one switch to a port on another switch. An ISL can “break” if the cable is unplugged or if a port on one of the switches is disabled or goes into a faulty state. This breakage may be planned by a storage administrator or unplanned if, for instance, a cable is accidentally unplugged. If all ISLs between one set of switches and another set of switches in the fabric are broken, this results in fabric segmentation. A segmentation of one fabric means that the fabric splits into two fabrics: two sets of interconnected fibre channel switches that have no connectivity from one set to the other.
Storage management software is used by storage administrators for multiple tasks, including understanding the connectivity (topology) of a SAN and knowing the properties and states of fibre channel switches and storage devices connected to the SAN. A storage management software application may use “agents,” also referred to as “data sources,” to collect the latest available information about the topology and the switches and devices on the SAN. The agents are responsible for providing such information to client applications through standard or proprietary interfaces. Examples of “agents” are storage management initiative specification (SMIS) agents, common information model (CIM) object manager (OM) (CIMOM) agents, Brocade® switches that are Brocade® application program interface (API) servers, simple network management protocol (SNMP) agents, and host in-band fabric agents that collect fabric information in-band.
Certain types of agents communicate to only one switch in each fabric and can be configured programmatically to manage more than one fabric. In order to manage more than one fabric, one switch for each fabric must be configured with the agent. In one example, the agent may communicate with the one proxy switch for the fabric in order to gather information about all devices for the fabric. If fabric segmentation occurs, the switches and devices on the fabric that does not contain the proxy switch become no longer visible to the agent. Note that for this type of agent, there is no point in configuring the agent with all switches in a fabric in advance in anticipation of an accidental segmentation. The agent only communicates to the first proxy switch even after fabric segmentation.
Thus, fabric segmentation presents a problem for storage management applications. A user of a storage management application may have set up a regularly scheduled inventory collection, also referred to as a probe, of the fabric through the agent. If the fabric segments, the agent no longer provides information on a set of the switches and devices, because these are now on a separate fabric for which the agent is not configured. The new fabric is not visible to the agent because the agent is only configured with one switch from the original fabric.
A user may be aware of the fabric segmentation—either because it was planned or because the storage management application has detected the segmentation and alerted the user—but the user may not be aware that the scheduled fabric probe no longer collects information on devices for which it had formerly collected information. The storage management application has completely lost communication with a set of fibre channel switches, and the user cannot manually add the newly formed fabric to the scheduled probe job because no agent knows any properties, including the world wide name (WWN) of the fabric, or other information for the new fabric.
Furthermore, a switch may move from one fabric to another, or two fabrics may merge to form one fabric even though the sets of switches are unchanged. In addition, a new switch may be added to a fabric, which may change the WWN of the fabric. The WWN is a unique identifier for an entity, such as a port, switch, or the fabric itself. The fabric may get its WWN from a switch; however, when a new switch joins the fabric, it may change the WWN of the fabric.
One known solution is to redesign the behavior of the fabric agent so that the agent automatically reconfigures itself to manage both fabrics after fabric segmentation. However, there are existing agents, such as the Brocade® SMIS agent, which do not automatically reconfigure themselves. Thus, this solution does not work for many existing fabrics today.
Another solution is for the storage administrator to use multiple agents for redundancy. Each agent can be configured with a switch in the fabric, and all agents can manage the same fabric. For proxy agents, such as the Brocade® SMIS agent, this requires a server to be used to host each agent. Having many servers to host separate agents for the same fabric is unfavorable with storage administrators.